The government is set to impose one of the toughest regimes in the world on the mobile phone industry, with a crackdown on the building of masts and a call for companies to stop marketing to children.

Operators were privately seething at the clampdown. It comes days after the industry agreed to pay the Treasury £22.5bn for third-generation phone licences.

Ministers were prompted to act after publication of a government-sponsored report on the safety of mobiles that highlighted potential risks to children. "The timing of the publication of this report has to be suspect to say the least," one executive said. "We all think this is a scandal," said another operator.

Yvette Cooper, public health minister, said she was "minded" to accept the report's recommendations that all new masts would have to pass full planning procedures. She would consult before deciding.

Masts under 15m are currently subject to less onerous procedures.

The system would represent probably the toughest planning regime in the world. It is thought no other country tries to restrict marketing of mobile phones.

Restrictions on future masts could impose severe complications and costs for companies preparing networks for the new phone services.

The procedures would be a burden to all operators but would bear down heavily on a new operator with a full network to construct. All licence-winners in the recent auction for next-generation services must build a network covering 80 per cent of the population by 2007.

For a new operator such as TIW - winner of the licence reserved for new entrants - the only way to complete the network on time would be to share competitors' masts. Rivals have many ways of making this kind of co-operation difficult. "The government cannot have it both ways," a person close to TIW said yesterday. "We shall be seeking and will expect its help to share facilities."

Other countries with big mobile phone markets - such as Sweden and Finland - have carried out extensive research on health risks but none has followed up with safety guidelines.

The safety report, commissioned by the government and led by Sir William Stewart, a former government chief scientist, said on balance the evidence did not suggest mobile phone emissions and transmitters presented any risk.

But he said much more research was needed and children should be discouraged from using mobiles.

The government yesterday announced research into the potential health hazards of mobile phones and asked the industry to meet half the cost.

Ministers have also instructed Professor Liam Donaldson, chief medical officer, to draw up clear guidelines.

Parents' groups complained the report left them confused.

Ministers were forced to cobble together their response after the Stewart report failed to make recommendations, such as an age limit or how long children could safely spend on mobile phone calls.

Sir William said he would not give his grandchildren - aged four and two - unfettered access to mobiles.